1 2HPSA - Hewlett Packard Smart Array driver
3-----------------------------------------
4 5This file describes the hpsa SCSI driver for HP Smart Array controllers.
6The hpsa driver is intended to supplant the cciss driver for newer
7Smart Array controllers. The hpsa driver is a SCSI driver, while the
8cciss driver is a "block" driver. Actually cciss is both a block
9driver (for logical drives) AND a SCSI driver (for tape drives). This
10"split-brained" design of the cciss driver is a source of excess
11complexity and eliminating that complexity is one of the reasons
12for hpsa to exist.
13 14Supported devices:
15------------------
16 17Smart Array P212
18Smart Array P410
19Smart Array P410i
20Smart Array P411
21Smart Array P812
22Smart Array P712m
23Smart Array P711m
24StorageWorks P1210m
25 26Additionally, older Smart Arrays may work with the hpsa driver if the kernel
27boot parameter "hpsa_allow_any=1" is specified, however these are not tested
28nor supported by HP with this driver. For older Smart Arrays, the cciss
29driver should still be used.
30 31The "hpsa_simple_mode=1" boot parameter may be used to prevent the driver from
32putting the controller into "performant" mode. The difference is that with simple
33mode, each command completion requires an interrupt, while with "performant mode"
34(the default, and ordinarily better performing) it is possible to have multiple
35command completions indicated by a single interrupt.
36 37HPSA specific entries in /sys
38-----------------------------
39 40 In addition to the generic SCSI attributes available in /sys, hpsa supports
41 the following attributes:
42 43 HPSA specific host attributes:
44 ------------------------------
45 46 /sys/class/scsi_host/host*/rescan
47 /sys/class/scsi_host/host*/firmware_revision
48 /sys/class/scsi_host/host*/resettable
49 /sys/class/scsi_host/host*/transport_mode
50 51 the host "rescan" attribute is a write only attribute. Writing to this
52 attribute will cause the driver to scan for new, changed, or removed devices
53 (e.g. hot-plugged tape drives, or newly configured or deleted logical drives,
54 etc.) and notify the SCSI midlayer of any changes detected. Normally this is
55 triggered automatically by HP's Array Configuration Utility (either the GUI or
56 command line variety) so for logical drive changes, the user should not
57 normally have to use this. It may be useful when hot plugging devices like
58 tape drives, or entire storage boxes containing pre-configured logical drives.
59 60 The "firmware_revision" attribute contains the firmware version of the Smart Array.
61 For example:
62 63 root@host:/sys/class/scsi_host/host4# cat firmware_revision
64 7.14
65 66 The transport_mode indicates whether the controller is in "performant"
67 or "simple" mode. This is controlled by the "hpsa_simple_mode" module
68 parameter.
69 70 The "resettable" read-only attribute indicates whether a particular
71 controller is able to honor the "reset_devices" kernel parameter. If the
72 device is resettable, this file will contain a "1", otherwise, a "0". This
73 parameter is used by kdump, for example, to reset the controller at driver
74 load time to eliminate any outstanding commands on the controller and get the
75 controller into a known state so that the kdump initiated i/o will work right
76 and not be disrupted in any way by stale commands or other stale state
77 remaining on the controller from the previous kernel. This attribute enables
78 kexec tools to warn the user if they attempt to designate a device which is
79 unable to honor the reset_devices kernel parameter as a dump device.
80 81 HPSA specific disk attributes:
82 ------------------------------
83 84 /sys/class/scsi_disk/c:b:t:l/device/unique_id
85 /sys/class/scsi_disk/c:b:t:l/device/raid_level
86 /sys/class/scsi_disk/c:b:t:l/device/lunid
87 88 (where c:b:t:l are the controller, bus, target and lun of the device)
89 90 For example:
91 92 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat unique_id
93 600508B1001044395355323037570F77
94 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat lunid
95 0x0000004000000000
96 root@host:/sys/class/scsi_disk/4:0:0:0/device# cat raid_level
97 RAID 0
98 99HPSA specific ioctls:
100---------------------
101 102 For compatibility with applications written for the cciss driver, many, but
103 not all of the ioctls supported by the cciss driver are also supported by the
104 hpsa driver. The data structures used by these are described in
105 include/linux/cciss_ioctl.h
106 107 CCISS_DEREGDISK
108 CCISS_REGNEWDISK
109 CCISS_REGNEWD
110 111 The above three ioctls all do exactly the same thing, which is to cause the driver
112 to rescan for new devices. This does exactly the same thing as writing to the
113 hpsa specific host "rescan" attribute.
114 115 CCISS_GETPCIINFO
116 117 Returns PCI domain, bus, device and function and "board ID" (PCI subsystem ID).
118 119 CCISS_GETDRIVVER
120 121 Returns driver version in three bytes encoded as:
122 (major_version << 16) | (minor_version << 8) | (subminor_version)
123 124 CCISS_PASSTHRU
125 CCISS_BIG_PASSTHRU
126 127 Allows "BMIC" and "CISS" commands to be passed through to the Smart Array.
128 These are used extensively by the HP Array Configuration Utility, SNMP storage
129 agents, etc. See cciss_vol_status at http://cciss.sf.net for some examples.
130 131